Water heating coil



HanpW, l939. Y P. HAGENSON ET AL 2,143,874

WATER HEATING COIL Filed'Maroh 1e, 1937 P 755-]- I Z/ Patented Jan. 17, 1939 UNETED STATES WATER HEATING COIL Poder Hagenson and Martin F. Hanson, Detroit Lakes, Minn.

Application March 16,

1 Claim.

This invention relates to water heating devices and particularly to a water heating coil adapted to be disposed in close proximity to the flames of an oil burner or the rire in a iirebox of any ordinary furnace.

One object of the invention is to provide a coil which will speed up heat eiiiciency and yet Secure a great saving of fuel in the newer types of boilers and in old types of boilers.

Another object is to provide a water heating coil so disposed in the furnace that the entire surface will come in direct contact with the flame and which is so constructed that it can be placed in position where it receives the maximum heat, that is, where it is submerged in the flame itself.

A further object in this connection is to provide a coil which, when used with an oil burner, wil act as a baffle 'causing the flames of the oil burner to come into intimate Contact with the coil and preventing waste of heat.

A further object is to provide a water heating coil in which the tubing used is of a size not less than 3 in. in diameter so as to prevent scale forming within the pipe or tube and in which resistance to circulation is reduced to a minimum.

Other objects will appear in the course of the following description.

Our invention is illustrated in the accompanying drawing wherein:

Figure l is a vertical section on the line I--I of Figure 2.

Figure 2 is a section on the line 2-2 of Figure 1.

Figure 3 is a detail section through one portion of the coil showing the manner in which the coil is constructed.

The coil Ill shown particularly in Figure 2 is formed of tubing cr pipe having a diameter not less than 3 in, for the reasons hereinbefore stated. Materials used for tubing can be either steel, copper alloy or any other suitable material. The coil consists of a plurality cf longitudinally extending pipe sections li connected by short connecting pipe sections i2 having welded joints I3 at an angle of 45. The coil constructed as above extends longitudinally into the rebox or through the iirebox or above the fire in close approximation to the flames or glowing coals, then at right angles, then longitudinally, again at right angles, and so on zig-zagging, as it were, through the lirebox with the coils in close approximation to each other.

The furnace in which the coils are placed is diagrammatically shown and is designated A and is provided with a water spa'ce B, but it is to be 1937, Serial N0. 131,224

understood that while we have shown a water heating boiler or furnace, we do not wish to be limited to the use of our coil in a water heating furnace.

We have illustrated diagrammatically at C an oil burner and C is intended to represent any of the very many oil burners on the market today. The coil is placed so close to this oil burner that the coil will be immersed, as it were, in the flames from the burner and, of course, if this coil is used in connection with a coal furnace, the coil will be disposed at the lowest portion of the rebox immediately above the glowing coals thereof so as to receive a maximum of heat therefrom.

This 'coil disposed as it is immediately above the burner C and with the convolutions of the coils disposed close to each other, acts as a baiiie causing the flames to come in intimate contact with the coil I U and securing a maximum heating of the Water in the coil.

One end of the coil I0, as illustrated in Figure 2, is coupled by a coupling I4 to an outlet pipe I5 to which a pipe section I 5 is welded. To this pipe section I6 is welded a second long section IT which extends along the exterior of the furnace A and then inward toward the middle of the furnace and connects with a return pipe I8 leading from a radiator or radiator system. The inlet pipe I9 extends through the furnace wall and is coupled at 2B to the inlet end of the coil I by any suitable coupling as, for instance, the coupling I4 previously referred to. A riser pipe 2| extends upward from the inlet pipe I9 and is connected to the inlet pipes for the radiator 4system.

It will be seen that our coil is so constructed that the entire surface is disposed in the most effective position for heating. Our coil would be disposed on a level with the lowest portion of the boiler or furnace and the lowest temperature of water thereby giving the coil the maximum circulation at all times.

The coil is very simple and easy to install either in an old type of boiler or in the latest oil burning units or without any alteration of the boiler or furnace unit. Our construction is such that it is possible to accommodate the greatest number of different types of boilers. By using large-sized tubing, not less than 3 in. in interior diameter, a maximum circulation is secured and such tubing will not scale. A coil made of smaller diameter than this resists circulation and thus tends to give the smaller tubing a greater chance to scale. This coil in actual practice has been found to speed up the heat efficiency of room radiators with a saving of fuel, in the newer types of boilers, of more than and in the older makes of boilers, the efficiency is found to be increased by approximately 50% with a saving in fuel of about the same percentage. This coil can be used successfully with either wood or coal burning furnaces or with coal stokers. It can also be used successfully in hot air furnaces for the purpose of heating water or securing steam.

It will be noted that the coil I0 is disposed below the door opening D sho-wn in Fig. 1. This permits the coil, in case of any failure in the oil burner, to work properly to act as a grate, so that coal or wood may be placed upon the coil l0 as upon a grate and the furnace can still operate successfully.

It will be seen that this heating unit is so lo cated as to get the benet of the fire where the lire is hottest and that it provides a very great area of heating surface, thus obtaining quicker action. Inasmuch as the pipes which form the convolutions of the coil are relatively large, the pipes will not burn out as will piping of smaller dimensions. Inasmuch as the coil is made up entirely of boiler steel, it is not affected by expansion or contraction, which is not true of units formed of dissimilar materials. Because of the baffling character of the coil, its use greatly decreases the stack temperature and correspondingly increases the efficiency of the boiler. In actual practice, we have found by tests that before the installation of our coil, that in many cases the stack temperature was '750 and more, but that after the installation of this coil, this temperature was reduced to 250. Calculations by engineers have shown that this secures a saving in fuel consumption of while the intensity of the heat in the re box was increased 500. 'Ihis water heating unit can be installed Without in any way altering the furnace or boiler and, as before stated, hand firing can be done in case of emergency caused by the failure of the oil burner.

It is to be understood that this invention relates particularly to the coil l0 and that the pipes I5, I6, Il, I8, I9 and 2| may be made of ordinary pipe fittings, that is, standard pipe fittings composed of standard pipe lengths and elbows or Ts.

What is claimed is:

The combination with a furnace having a fire pot, a door above the fire pot and an oil burner disposed within the re pot, of a Water heating coil extending back and forth in a single horizontal plane within the re pot immediately above the oil heater and below the door, the coil being disposed in the Zone of greatest heat, the coil having a uniform diameter throughout its entire length, the diameter of the coil being at least three inches, and the convolutions of the coil being relatively 'close to each other.

PEDER HAGENSON. MARTIN F. HANSON. 

